Yankees Once Again Show Their Bad Side, at a Bad Time

Loss to Boston Hurts New York in Playoff Race as Time Grows Short

As they have for so much of this disappointing season, the Yankees kicked off their September schedule Tuesday suffering from a case of multiple personalities.

They are mediocre—underwhelming on offense, worse on defense—but they are better right now than they've been for much of the season, winning nine of their past 16 entering Tuesday's game against the Red Sox. They go on winning streaks like their five-gamer last week, then...